import { Light } from './Light.js';
import { SpotLightShadow } from './SpotLightShadow.js';
import { Object3D } from '../core/Object3D.js';

class SpotLight extends Light {
  constructor(color, intensity, distance = 0, angle = Math.PI / 3, penumbra = 0, decay = 1) {
    super(color, intensity);

    this.type = 'SpotLight';

    this.position.copy(Object3D.DefaultUp);
    this.updateMatrix();

    this.target = new Object3D();

    this.distance = distance;
    this.angle = angle;
    this.penumbra = penumbra;
    this.decay = decay; // for physically correct lights, should be 2.

    this.shadow = new SpotLightShadow();
  }

  get power() {
    // intensity = power per solid angle.
    // ref: equation (17) from https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf
    return this.intensity * Math.PI;
  }

  set power(power) {
    // intensity = power per solid angle.
    // ref: equation (17) from https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf
    this.intensity = power / Math.PI;
  }

  dispose() {
    this.shadow.dispose();
  }

  copy(source) {
    super.copy(source);

    this.distance = source.distance;
    this.angle = source.angle;
    this.penumbra = source.penumbra;
    this.decay = source.decay;

    this.target = source.target.clone();

    this.shadow = source.shadow.clone();

    return this;
  }
}

SpotLight.prototype.isSpotLight = true;

export { SpotLight };
